The present invention relates to a support and guide device suitable for the kind of adjustable seats often fitted to automobiles. Such devices include a pair of fixed guides, which in use are attached to the floor of the automobile, each of which comprises a pressed sheet metal strip having a rather flattened U-shape in cross section with a base portion and two lateral flanges directed outwardly, and a pair of movable guides which in use are attached to the seat structure and each of which comprises sheet metal strip also having a generally flattened U-shape in cross section, with a base portion and two side portions which latter are folded to form lateral channels so shaped that when the movable guides are inverted and attached to the underside of a seat structure the channels surround respective flanges of the fixed guides and can slide axially along them. One pair of guides (i.e. one fixed and one movable guide) is provided with means fixing the guides in a selected relative position, such means usually comprising a series of notches in the fixed guide into which can engage one or more teeth on an adjustment shaft or lever mounted on the seat structure and provided with a control level or knob manually operable to disengage the tooth or teeth from the notches and resiliently biased towards a position of engagement of the tooth or teeth in the notches.
In one known device of this kind, the teeth are carried on a shaft which extends parallel to the length of and is mounted rotatably on an outer part of one of the movable guides; and the cooperating notches are formed in the edge of the outer flange of the associated fixed guide. At the position where the tooth or teeth project from the shaft, a length of the side portion on one side of the movable guide is removed to allow access for the tooth or teeth to engage in the notches.
A fundamental disadvantage of an adjustment mechanism of this kind is that the notches and teeth both have exposed sharp edges which may cause injury or tear clothing.